Pneumatic weir water level control for cooling tower hot water distribution basin

ABSTRACT

A weir assembly has a rotatable weir member whose position for water level control or water diversion is governed by inflation or deflation of a collapsible wall, pneumatically operated tube supporting the weir member. The tube underlies the weir member in disposition such that charging and discharging of air from the tube to vary its cross-sectional size correspondingly raises and lowers the weir member. Segregation of the water flow in the hot water distribution basin of a water cooling tower may thereby be controlled to either vary the cooling capacity of the tower by changing the extent or pattern of water loading on an evaporative cooling structure below the distribution basin thereby affecting its cooling capacity or, in the case of a cooling tower having both wet and dry cooling sections served by a common air mover, to permit not only variation of respective water loadings but also the relative quantities of air permitted to pass through corresponding wet and dry sections. Use of the weir assembly adjacent one outer extremity of the distribution basin also permits effective prevention of ice formation on the inlet louvers associated with the evaporative cooling structure of the tower by the expedient of simply periodically raising the weir member of the assembly to a point where hot water from the distribution basin is caused to overflow the basin end wall and thereafter cascade down the louvers to the cold water collection basin.

United States "Patent J [191 Cates et al. 2

[111 3,794,304 {[451 Feb.26, 1974 1' PNEUMATIC WEIR WATER LEVEL CONTROLFOR COOLING TOWER HOT WATER DISTRIBUTION BASIN 751 Inventors: Robert E.Cates, Leawood, Kansx,

Robert M. Mitchell, Kansas City, Mo.

' [73] Assignee: The Marley Company, Mission,

Kans. I

[22] Filed: June 19,1972 [21] Appl. No.: 264,147- h '52 us; Cl261/1ll,26 l/D1G. 11,55/226,-

t 251/61 [5-1] Int. Cl Boll 3/04 [58] Field'oi Search26 l/l l0, ll '1,'DIG. 11; 55/226; 25l/6l-6l.5

[ 56] References Cited A V UNITED STATESPATENTS 3,322,409 5/l967 Reed 26l/DlG. 11 3,635,042 1/1972 Spangemacher... 26l/DIG. 11 2,676,609 74/l954 Pf urrer 251/61 3,588,036 6/1971 .Harter.. 251/61 PrimaryExaminer-Tim R. Miles I 7 Assistant Examiner-Steven H. MarkowitzAttorney, Agent, or Firm-Schmidt, Johnson, l-lovey & I

Williams [571 7 ABSTRACT A weir'assembly has a rotatable weir memberwhose position for water level control or water diversion is governed byinflation or deflation of a collapsible wall,

pneumatically operated tube supporting the weir member. The tubeunderlies the weir member in disposition such that charging anddischarging of air from the tube to vary its cross-sectional sizecorrespondingly raises and lowers the weir member. Segregation of thewater flow in the hot water distribution basin of a water cooling towermay thereby be controlled to either vary the cooling capacity of thetower by chang? ing the extent or pattern of waterloading on anevaporative cooling structure below the distribution basin therebyaffecting its cooling capacity or, in the case of a cooling tower havingboth wet and dry cooling-sew tions served by a common air mover, topermit not only variation of respective water loadings but also therelative quantities of air permitted to pass through corresponding wetand'dry sections. Use of -the-weir assembly adjacent one outer extremityof the distribution basin also permits effective prevention of iceformation on the inlet lo'uvers associated with the evaporative coolingstructure of thetower-by the expedient of simplyperiodically raising;the-weir; member. of the assembly. to a point where hot water from thedistribution basin is caused to overflow the basinend wall andthereafter cascade down the louvers to the cold'water collectionqbasin.i

1 2 Claimsplll Drawing Figures PATENTEDFB26|974 3.794304 suzuaorz Hofwafer to Tower PNEUMATIC WEIR WATER LEVEL CONTROL FOR COOLING TOWER HOTWATER DISTRIBUTION BASIN c This invention relates to the field of watercooling towers and, more particularly, to means for controlling .thedepth or diversion of water collected in the hot water distributionbasin of such towers.

In conventional evaporative type water cooling towers it is oftennecessary or desirable to vary the temperl changes in the operatingcharacteristics of the equipment to which the cooled water iscirculated, such as the condenser of a power' generating facility. Inorder to accomplish this result, a part of the hot water may be divertedfrom the cooling structure of the tower to an appropriate extent inorder to reach the desired blended temperature level in the water whichis returned to the point of use.

Although temperaturecontrol by diversion of hot water as necessary forcontrol purposes is relatively straight forward in equipmentrequirements and operating parameters thereof, the problems become morecomplex in the case of cooling towers of the type using both indirect,dry heat exchange units and direct, wet

heat exchange structure. This is true where the air flows-through thewet and dry sections in parallel or in series relationship. In theparallel air flow type of installation heated water is directedsuccessively through finned heat exchange tubes in which ambient airpassing in heat exchange relationship with the exterior of such tubesindirectly lowers the temperature of the water flowing therethrough, andthen through evaporative type heat exchange structure in which water isdispersed over a large area and allowed to gravitate in droplets overthe structure for direct impingement of cooling ambient air thereon. Thetwo parallel,.essentially separate airflows passed through the dry heatexchange tubes and the wet evaporative type heat exchange structurerespectively are subsequently drawn into the plenum chamber of the towerfor mixture with one another to form an exhaust plume rising from thetower. v

ln both'types of wet-dry water cooling towers. the ambient airflow pastthe dry heat exchange tubes does not, of course, pick up moisture as itis drawn into the plenum chamber of the tower; however, the ambientairflow through the wet, evaporative type heat exchange structurenecessarily becomes heavily laden with moisture which is carried intothe plenum chamher for subsequent emission in the exhaust plume. From avisible plume standpoint, particularly on a cold day, the dry airflowposes no particular problems. However. depending upon the temperature ofthe surrounding air at the tower installation, the moisture ladenairstream may pose a problem, if theftemperature of the surrounding airis low enough to cause the moisture in the stream to condense, therebyproducing fog. Such creation of fog is. undesirable from severalstandpoints including its nuisance effects as the fog settles onneighboring surfaces in the vicinity of the cooling tower.

The formation of fog in this manner can be controlled to a large extentby regulating the proportion of dry air in the plume from the dry heatexchange tubes relative to moist air in the plume mixture from the wetheat exchange structure. To this end, by correlating the amount of dryair necessary in the plume with the temperature of air surrounding thetower and appropriately sizing the dry tube heat exchangers and the wetheat exchange structure, a plume having the desired fog abatementqualities may be produced.

However, conventional means of controlling the temperature of the cooledwater issuing from the tower' have included simply bypassing a portionof the hot water around the tower to the extent necessary. Accordingly,the dry air drawn from the heat exchange tubes into the plenum chamberof the tower would not be heated to the extent which would be the caseif the water were not bypassed, which thereby diminishes the fogabatement capabilities of the tower. Also, it is beneficial, for besthydraulic distribution, to maintain a maximum flow to the dry heatexchange sections. With- 1 out the presence of dry air from the heatexchange structure there is an increased tendency to produce fog.

Aside from the plume abatement problem, it is also desirable in awet-dry cooling tower to be able to effectively control the relativeefficiencies of the wet and dry sections by regulating the amount of airwhich passes through each of the sections or the disposition of the hotwater relative to the cooling air-streams.

Accordingly, one important object of the present invention is to provideimproved water temperature control through the provision of anactuatable weir assembly which may be located in the hot waterdistribution basin of a water cooling tower for stratifying the waterlevel in the basin in variable amounts whereby to correspondingly varythe water loading on cooling structure receiving the stratified flowfrom the distribution basin.

Another important object of the present invention is to provide improvedwater temperature control in parallel airflow path water cooling towerswithout diminishing the fog abatement capabilities of such tower bydisposing an actuatable weir assembly of the aforesaid character in thehot water distribution basin of the tower downstream from the dry heatexchange tubes thereof and .upstream from the wet, evaporative type heatexchange structure thereof so that water may be selectively bypassed tothe extent necessary around the evaporative structure. In this mannerwarm, dry air from the dry heat exchange tubes is always available tothe extent necessary 1 in the plenum chamber of the tower to abate fogformation.

Also an important object of the present invention is to provide wet-drycooling tower structure embodying an adjustable weir assembly asdescribed which is operable to permit water from the dry cooling sectionto be diverted from the underlying fill assembly and caused to cascadedown the air inlet face of the fill assembly in partial or substantiallycomplete blocking relationship to airflow through the fill therebyproviding selective variation of the coolingefficiencies of the wet anddry tower sections respectively.

An additional important object of the instant invention is to obtainimproved control of ice formation on the louvered, ambient airflowinlets associated with evaporative heat exchange structure of a watercooling tower by providing an actuatable weir assembly adjacent oneextremity of the hot water distribution basin of the tower above thelouvered inlets so that the weir assembly may be used to selectivelyrelease an overflow of water from the basin to the louvered inlets asrequired to avoid or eliminate ice formation at the louvered inlets.

A further important object of this invention is the provision of anadjustable weir assembly for use in the hot water distribution basin ofwater cooling towers wherein a multipositionable weir member of theassembly is controlled by a collapsibly walled, hollow element whichreceives and discharges pressurized control fluid in an amount necessaryto effect shifting of the member between its various positions.

Yet-another important object of the present invention is to provide aweir assembly as'set forth above wherein the weir member thereof isshiftable by its control element not only between various positions forstratifying the water level in the distribution basin, but also to aposition or positions causing overflow of the water from thedistribution basin to entirely bypass at least a certain proportion ofthe cooling structure which would otherwise receive water from thedistribution basin.

In the drawings:

FIG. I is a fragmentary, vertical cross-sectional view of a weirassembly constructed in accordance with the present invention andinstalled in the hot water distribution basin of a water cooling tower,the maximum bypass position of the weir member of the assembly beingindicated by solid lines and its neutral position being indicated byphantom lines;

FIG. 2 is a fragmentary, front elevational view of the weir assembly atone end of the latter showing adjacent parts of the distribution basinin cross section for clary;

FIG. 3 is a fragmentary, cross-sectional view of the opposite end of theassembly with the weir member in its lowered, neutral position and takenalong line 3-3 of FIG. 1;

FIG. 4 is a fragmentary, top plan view of the assembly;

as an icing control means for the louvered ambient airflow inlets of thetower.

Referring initially to FIGS. 1-4, the weir assembly 20 includes anelongated weir member 22 formed of sheet material and supported forswingable inclination on the floor 24 of distribution basin 26 by atrough-like mounting support 28. Support 28 is cross-sectionallyU-shaped with spaced-apart, upstanding, front and rear legs 30 and '32respectively, the rear leg 32 having a plurality of longitudinallyspaced-apart, T-shaped hinge units 34 affixed thereto. Each hinge unit34 comprises an upstanding web 36, joined to leg 32 and the bottom 38ofsupport 28, and a crosshead 40 extending longitudinally of support 28with its lowermost, longitudinal edge spaced above bottom 38. A seriesof longitudinally spaced drain openings 42 are provided in sup port 28along the respective junctions of legs 30 and 32 with bottom 38. l

Member 22 includes a main planar portion 44 for deflecting water flowand is provided at its outer end with 36 of units 34 during suchswinging or member 22.-

Also, as shown in FIG. 1, the front leg 30 of support 28 serves as astop which is engageable with the lower face of planar portion 44 tolimit swinging of member 22 in a downward direction within basin 26.

Assembly 20 also includes means for controlling the swinging of member22 between its inclined positions in the nature of a collapsibly walled,synthetic resin fiber reinforced control tube element 52 which isreceived by support 28 against the front leg 30 thereof and extends inunderlying relationship to member 22 forwardly of the hinge units 34 ofsupport 28. As shown best in FIGS. 2 and 3, the member 22 and itssupport 28 extend longitudinally between opposed, upright components ofbasin 26 which may, for example, be an outer wall 54 at one end of theassembly 20 as shown in FIG. 2, or a partition 56 at the opposite end ofassembly 20 as shown in FIG. 3. In both cases, the member 22 and itssupport 28 terminate at the respective upright component, but thecontrol tube 52 extends therethrough for projection beyond 'wall 54 andpartition 56 respectively. At the partition end of tube 52 a cap 58 isprovided, and at the wall end of tube 52 an inlet fitting 60 is providedfor a line 62 supplying control fluid such as air to tube 52.

Tube 52 may be so constructed as to assume a crosssectionallycylindrical configuration when in a pressurized condition so that tube52 may fit snugly through suitable passages in wall 54 and partition 56.In this manner a sealing fit may be established so that water is notlost from basin 26 around tube 52. Moreover, to insure that member 22does not deform tube 52 in the vicinity of wall 54 and partition 56,member 22 is provided with a pair of relieved portions at oppositelongitudinal ends of member 22 which may be conical in configuration forcomplementally receiving corre- -sponding sections of tube 52 withoutdepressing the same during downward swinging of member 22.

FIGS. 6-8 illustrate on a large scale one contemplated utilization ofassembly 20. A parallel, airflow path cooling tower is schematically andfragmentarily shown in these Figures having its hot water distributionbasin 26 provided with outlet orifices 66 in floor 24, evaporative type,wet cooling structure 68 designated fill and disposed directly belowbasin 26, and a cold water collection basin 70 disposed in underlyingrelationship to structure 68 for receiving cooled water therefrom. Theouter side of structure 68 is provided with louvered, ambient air inlets72 which direct the ambient air across the fill structure 68 forsubsequent entry into the plenum chamber of the tower located at theopposite side of structure 68.

Above basin 26 in upstream relationship thereto, is disposed a hot waterinlet header 74 for supplying water to parallel sets of dry, heatexchange tubes 76. By way of example only, the tubes 76, shown in FIGS.6-8, are of the double-pass type in which water from header 74 isinitially directed upwardly through a pair of righthand tubes 76 forindirect heat exchange with an ambient airstream flowing against theelevated pairs of tubes 76 toward the plenum chamber of the tower andthen,

is directed downwardly through a second pair of the tubes 76 for furtherindirect heat exchange with the airflow and for subsequent dischargeinto basin 26.

Although not illustrated in detail in FIGS. 6-8, its is understood thatthe evaporative heat exchange structure 68, designated as fill is ofconventional nature and may, for example, comprise a series ofhorizontally and vertically spaced, generally horizontally disposedslatscarried by a suitable corrosion-resistant, supporting grid so thatwater gravitating from orifices 66 in basin 26 contacts the slats and isrepetitively broken up principally into droplets, although certainproportions also form films of water over successive slats before thecooled water is finally received in collection basin face of the fill.Bypass of water outboard of the fill assembly also serves as aneffective anti-icing system for cold weather operation of the coolingtower.

The specific position of assembly within basin 26 may be varied withoutimpairing its principles of operation, but it is suggested, as shown inFIGS. 6-8, that assembly 20 may be positioned to the left of center ofbasin 26 so that a majority of orifices 66 are left dry when member 22is in its full bypass position of FIG. 8.

The position of member 22 as controlled by tube 52 may be regulatedmanually or by means of an automatic control system, one specificexample of which is 70. Although the fill construction thus described isconventional for a crossflow type of tower as illustrated in FIGS. 6-8,it is to be understood that other equivalent fill structures may be usedwith equal-facility in the present invention without departing from theprinciples thereof.

In operation, the weir assembly 20 may be positioned as shown in FIGS.6-8, within basin 26 for regulating thewater flowing within basin 26toward outlet orifices 66 thereof. By discharging a predetermined amountof air from tube 52 through line 62, the weir member 22 may be restedupon leg 30 of support 28 in its lowermost, neutral position'indicatedin FIGS. 1 and 6. In this position it may be seen that the tube 52 issubstantially collapsed to allow member 22 to remain in its loweredposition. Thus, water in" basin 26 establishes a uniform head throughoutso that equal water loading exists on the evaporative structure 68.

For a number of reasons it may be desirable to change the temperature ofthe water collecting in collection basin 70. This is accomplished byinflating tube 52 with a predetermined amount of pressurized air toexpand tube 52 from its collapsed condition a sufficient extent to raisemember 22 to a desired height. As shown in FIG. 7, such procedureresults in a stratification of the water level in basin 26 such that theflow through outlet orifices 66 is at two different rates, resulting inuneven water loading on the evaporative structure 68. Thus, watergravitating into collection basin 70 is of two different temperaturescorresponding toits stratification in basin 26 to thereby change theaverage temperature of the body .of water collected in Water containedon the left side of assembly 20, viewing FIG. 8, still gravitates inpartthrough a portion of the orifices 66 and hence through thefillstructure 68 therebelow, but the portion of basin 26 to the right ofassembly 20 is nearly dry so that very littlewater is delivered to thecorrespondinglfill structures 68 below such portion. Accordingly, inthis position, assembly 20 causes the maximum differential in waterloading on fill structures 68 and results in the maximum reduction ofthe cooling efficiency of evaporative structure 68, not only because ofbypass of the water around the fill but also because of blockage ofairflow through the air inlet shown in FIG. 5. Such system employsathermally, hydraulically or pneumatically responsive sensor which may belocated at a number of possible positions in the water flow stream suchas, for example, upstream of the cooling apparatus as shown in FIG. 5,ordownstream' therefrom in the cooled water issuing from collectionbasin '70. Sensor 78 is operatively coupled with a pneumaticallyoperated controller 80 which receives operating air from an input line82 coupled with a supply line 84. An output line 86 from controller 80communicates the latter with a diaphragm type relay 88 having a bleedline 90 and an output line 92 which may correspond to the input line 62for control tube 52. One side of the diaphragm in relay 88 communicateswith line 86 from controller 80, while the opposite side receives asupply of pressurized air from line 94 coupled with supply line 84. Theside of the relay diaphragm receiving air from line 94 communicates withthe control tube 52 through the line 92 so that, by varying the amountof operating air supplied to relay 88 to flex the diaphragm, aproportional amount of air is delivered to the tube 52.

The above described system is especially adapted for installations inwhich the controller 80 may be disposed at a relatively great distancefrom tube 52. Moreover, it is especially suited for those installationsin which tube 52 is of great length. Thus, it is necessary and desirableto provide the relay 88 which governs the distribution of pressurizedair from line'94 into tube 52. In those installations in which thedistance between controller 80 and tube'52 is not so great and tube 52isof relatively nominal length, the use of relay 88 and line 94 may beeliminated with controller 80 communicating directly with tube 52. It isto be appreciated that the controller 80 also may be either theelectrically, hydraulically or pneumatically actuated type.

FIGS. 9 and 10 illustrate another way in which the weir assembly may beused for controlling the efficiency of the wet and dry sections of aparallel path wet-dry cooling tower as well asto preclude significanticing of inlet louvers 172. In this arrangement, the distribution basin126 of the cooling tower is provided with an inner hot water basin wall126b for containing the water against escape, while the outer outboardbasin wall 126a is lower than wall 1261:. Assembly 120 is locatedadjacent outer basin wall 1260 and as is apparent from the showing of FIGS'. 9 and 10, the bottom wall of basin 126 is devoid of water deliveryorifices in the area thereof between wall 126a and assembly 120.Similarly, the plan area of fill'assembly 168 underlying basin 126 issubstantially equal to the. area of basin between inboard wall 12612 andassembly 20 thus leaving a space free of fill between inlet louvers 172and the air inlet face of fill 168. The actual extent of this fill freespace has been somewhat exaggerated in the schematic 7 showings of FIGS.9 and 10 for clarity and it will be obvious to those skilled in this artthat the actual extent of the fill free area may be varied as desiredfor a particular installation.

The mode of operation of weir assembly 120 in the tower illustrated inFIGS. 9 and 10 is similar to that previously described in that uponmaximum inflation of the control tube 152, the water diverting member122 confines water inthe area between assembly 120 and outboard wall1260 (FIG. 10) so that such water is forced to overflow the top of wall126C and thereby cascade down inlet louvers 172 to the collection basin170. The fill 168 is thus maintained relatively free of hot water andthe efficiency of the evaporative cooling section as compared to the drycooling section, may be drastically reduced and in many instancesrendered virtually ineffective. This is because of diversion of hotwater away from the area of hot water basin 126 so that water cannotgravitate through the orifices 166 thereof, coupled with blockage of airthrough fill 168 by the vertical wall of water cascading down inletlouvers 172.

As previously explained, overflow of water onto the louvers 172 also maybe used to effect de-icing thereof if required in cold weatheroperation, with the weir member 122 being returned to its normally lowerposition when the louvers have been fully de-iced.

In the deflated condition of control tube 152, member I22 pivotsdownwardly to a point where hot water may fully cover the bottom wall ofbasin 126 for gravitation through orifices 166 into the fill assembly168 therebelow;

As with the installation of FIGS. 6-8,'assembly 120 as embodied in thetower structure of FIGS. 9 and 10, may be manually operated orautomatically controlled by a system as illustrated in FIG. 5.

We claim:

1. In a water cooling tower:

a hot water distribution basin forcollecting heated water from a supplysource and distributing the same forsubequent cooling thereof;

a cold water collection basin spaced from said distribution basin;

, cooling structure between said basins for receiving hot water fromsaid distribution basin, cooling the water. and directing the cooledwater into said collection basin,

said distribution basin being provided with a floor having a pluralityof outlets to said structure for maintaining a flow of the water in thedistribution basin toward said outlets; and

an actuatable weir assembly mounted at floor level in said distributionbasin and including a weir member projectable to a variable extent abovesaid floor for selectively stratifying water flow to said outletswhereby to correspondingly vary water loading on said cooling structurereceiving the Stratified flow,

said assembly including a collapsibly walled, hollow control elementoperably associated with said member for effecting said variableprojection of the member above said floor in response to the chargingand discharging of fluid into and out of said element. 2. In a watercooling tower as claimed in claim 1, wherein said element comprises asynthetic fiber reinforced tube.

3. in a water cooling tower asclaimed in claim 1, wherein saiddistribution basin has an overflow leading to said collection basin forbypassing said structure, said assembly being selectively operable todivert water to said overflow.

4. In a water cooling tower as claimed in, claim 1, wherein saidassembly is positioned in said basin to divert flow from at least amajority of said outlets when the assembly is operated to bypass flow tosaid collection basin via said overflow.

5. In a water cooling tower as claimed in claim 1, wherein said memberhas an inner end, said assembly further including means supporting saidmember adjacent said inner end for swinging movement toward and awayfrom said floor.

6. In a water cooling tower as claimed in claim 5,

wherein said element is disposed in underlying relationship to saidmember.

7. In a water cooling tower as claimed in claim 5, wherein said memberis swingable by said element to variable degrees of inclination relativeto said floor,

8. In a water cooling tower:

a hot water distribution basin for collecting heated water from a supplysource and distributing the same for subsequent cooling thereof;

a cold water collection basin spaced from said distribution basin;

fill assembly structure between said basins for receiving hot water fromsaid distribution basin, cooling the water, and directing the cooledwater into said collection basin;

a louvered ambient airinlet for said structure outboard of the latterfor introducing ambient air to the structure,

said distribution basin having wall means at the extremities thereofproximal to the air inlet and air outlet faces of the fill assemblystructure for containing water against escape from-the distributionbasin, in outboard wall means'adjacent the louvered air inlet beinglower than the inboardwall means; and

aweir' assembly adjacent the outboard wall means of the basin and havinga shiftable weir member for selectively controlling overflowof waterover said outboard wall means in response to raising and lowering of theshiftable weir member,

said assembly including means hingedly mountingsaid member for swingingmovement in the basin between a water retaining and a water releasingposition, and a hollow, collapsibly walled control element underlyingsaid member for effecting said swinging of the member between saidpositions in response to the charging and discharging of a control fluidinto and out of said element. 9. In a water cooling tower as claimed inclaim 8, wherein said assembly includes means hingedly mounting saidmember for swinging movement in the basin between a water retaining anda water releasing position, and a hollow, collapsibly walled controlelement underlying said member for effecting said swinging of the memberbetween said positions in response to the charging and discharging of acontrol fluid into and out of said element.

10. A cooling tower as set forth in claim 6 wherein is provided a drywater cooling section arranged to receive at least a part of the hotwater from said supply source prior to delivery thereof to saiddistribution bation basin and arranged to receive at least a part of thehot water from said supply source prior to delivery thereof to saiddistribution basin, there being means for moving ambient cooling' airstreams along separate paths through said dry cooling section and thefill assembly and to then combine such streams prior to return thereofto the surrounding atmosphere, said weir member being movable todispositions to vary the cooling capacity of the tower by changing theextent and pattern of water loading on the fill assembly and therelative amounts of cooling air permitted to pass through said drycooling section and the fill assembly respectively.

12. A cooling tower as set forth in claim 11 wherein said member ismovable to a location diverting substantially all of the water deliveredto the hot water distribution basin from the dry cooling section, awayfrom the fill assembly for cascade across the air inlet face of the tillassembly directly into the cold water collection basin.

1. In a water cooling tower: a hot water distribution basin forcollecting heated water from a supply source and distributing the samefor subequent cooling thereof; a cold water collection basin spaced fromsaid distribution basin; cooling structure between said basins forreceiving hot water from said distribution basin, cooling the water, anddirecting the cooled water into said collection basin, said distributionbasin being provided with a floor having a plurality of outlets to saidstructure for maintaining a flow of the water in the distribution basintoward said outlets; and an actuatable weir assembly mounted at floorlevel in said distribution basin and including a weir member projectableto a variable extent above said floor for selectively stratifying waterflow to said outlets whereby to correspondingly vary water loading onsaid cooling structure receiving the stratified flow, said assemblyincluding a collapsibly walled, hollow control element operablyassociated with said member for effecting said variable projection ofthe member above said floor in response to the charging and dischargingof fluid into and out of said element.
 2. In a water cooling tower asclaimed in claim 1, wherein said element comprises a synthetic fiberreinforced tube.
 3. In a water cooling tower as claimed in claim 1,wherein said distribution basin has an overflow leading to saidcollection basin for bypassing said structure, said assembly beingselectively operable to divert water to said overflow.
 4. In a watercooling tower as claimed in claim 1, wherein said assembly is positionedin said basin to divert flow from at least a majority of said outletswhen the assembly is operated to bypass flow to said collection basinvia said overflow.
 5. In a water cooling tower as claimed in claim 1,wherein said member has an inner end, said assembly further includingmeans supporting said member adjacent said inner end for swingingmovement toward and away from said floor.
 6. In a water cooling tower asclaimed in claim 5, wherein said element is disposed in underlyingrelationship to said member.
 7. In a water cooling tower as claimed inclaim 5, wherein said member is swingable by said element to variabledegrees of inclination relative to said floor.
 8. In a water coolingtower: a hot water distribution basin for collecting heated water from asupply source and distributing the same for subsequent cooling thereof;a cold water collection basin spaced from said distribution basin; fillassembly structure between said basins for receiving hot water from saiddistribution basin, cooling the water, and directing the cooled waterinto said collection basin; a louvered ambient air inlet for saidstructure outboard of the latter for introducing ambient air to thestructure, said distribution basin having wall means at the extremitiesthereof proximal to the air inlet and air outlet faces of the fillassembly structure for containing water against escape from thedistribution basin, in outboard wall means adjacent the louvered airinlet being lower than the inboard wall means; and a weir assemblyadjacent the outboard wall means of the basin and having a shiftableweir mEmber for selectively controlling overflow of water over saidoutboard wall means in response to raising and lowering of the shiftableweir member, said assembly including means hingedly mounting said memberfor swinging movement in the basin between a water retaining and a waterreleasing position, and a hollow, collapsibly walled control elementunderlying said member for effecting said swinging of the member betweensaid positions in response to the charging and discharging of a controlfluid into and out of said element.
 9. In a water cooling tower asclaimed in claim 8, wherein said assembly includes means hingedlymounting said member for swinging movement in the basin between a waterretaining and a water releasing position, and a hollow, collapsiblywalled control element underlying said member for effecting saidswinging of the member between said positions in response to thecharging and discharging of a control fluid into and out of saidelement.
 10. A cooling tower as set forth in claim 6 wherein is provideda dry water cooling section arranged to receive at least a part of thehot water from said supply source prior to delivery thereof to saiddistribution basin, there being means for moving cooling air streamsthrough said dry cooling section and the fill assembly respectively,said weir member being movable to dispositions to vary the coolingcapacity of the dry cooling section and fill assembly respectively bychanging the extent and pattern of water loading on the fill assemblyand the relative amounts of cooling air permitted to pass through saiddry cooling section and the fill assembly respectively.
 11. A coolingtower as set forth in claim 8, wherein is provided a dry cooling sectionadjacent said distribution basin and arranged to receive at least a partof the hot water from said supply source prior to delivery thereof tosaid distribution basin, there being means for moving ambient coolingair streams along separate paths through said dry cooling section andthe fill assembly and to then combine such streams prior to returnthereof to the surrounding atmosphere, said weir member being movable todispositions to vary the cooling capacity of the tower by changing theextent and pattern of water loading on the fill assembly and therelative amounts of cooling air permitted to pass through said drycooling section and the fill assembly respectively.
 12. A cooling toweras set forth in claim 11 wherein said member is movable to a locationdiverting substantially all of the water delivered to the hot waterdistribution basin from the dry cooling section, away from the fillassembly for cascade across the air inlet face of the fill assemblydirectly into the cold water collection basin.